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(N0 Modl.) 2 SheetsSheet 1.

F T. SCHMIDT. ELECTRIC ARC LAMP.

No. 495,601. Patented Apr. 18, 1893.

m: NORRIS PETERS co, wmaummwuuwcma. DV 0 (No Model.) 2 SheetsSheet 2.

F. T.v SCHMIDT. ELECTRIC ARC LAMP.

No. 496,601. Patented Apr. 18, 1893.

' UNTTED STATES PATENT @rrrcnt FREDERICK T. SCHMIDT, OF BRADFORD,ENGLAND.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 495,601, dated April18, 1893.

Application filed August 24, 1892. Serial No. 443,949. [No model.)Patented in England December 2, 1891.110. 21,018-

To ctZZ whom it may concern.-

Be it known that I, FREDERICK THOMAS SCHMIDT, asubject of the Queen ofGreat Britain and Ireland, residing at Bradford, in the county of York,England, have invented certain Improvements in the Construction ofElectrically-Controlled Arc Lamps, (for which I have obtained LettersPatent in England, No. 21,018, dated December 2, 1891,) of which thefollowing is a specification.

The object of this invention is to construct the operating portions ofarc lamps by a novel combination of parts arranged in such a manner thatthe are or distance between the carbons is positively formed, and thecarbons electrically controlled and adjusted according to theconsumption of the said carbons and thereby to produce a steady regularand uniform light, with less electrical energy by being enabled todispense with the aid of an electrical shunt or by pass.

In describing my invention in detail reference is made to theaccompanying sheet of drawings, representing so much of an arc lamp asis necessary to make clear my invention which is added thereto.

Figure l. is an elevation of an arc lamp frame fitted with myimprovement; Fig. 2. a view illustrating the opposite side of the same;Fig. 3. a plan drawn to a larger scale; Fig. 4. a sectional plan throughline a. b; Fig. 5. a sectional detail of the grooved pulley and theposition of the lever when under electrical control; Fig. 6. a similarsection showing the position of the lever when at rest, and Fig. 7. aplan of the grooved pulley showing the section of the compound groove inthe same.

Upon a suitable table A. above the carbons B and O. is mounted asolenoid D. the plunger or core E of which is prepared with an arm F.engaging with the slot hole cut in lever L. This lever is mountednearits center on a fulcrum pin J. and upon the said fulcrum pin ismounted a second lever L. the opposite end of which, when the electriccurrent is not passing through the lamp, is supported by an adjustablestop at K. The last named lever may be made to rest on the stop K. bymeans of aweight attached to or forming part of the said lever or by itsequivalent, a spring S. applied in the manner shown. A cord H. isattached to the lever L. and

passes over the pulley P. in the narrow portion G. of the compoundgroove, the otherend of the cord H. being attached to the second leverL. so that, when the arc is formed, the cord H. is kept tight in contactwith and grips the pulley P. to such an extent by means of the weightedlever L. or by its equivalent spring S. that the pulley P. is preventedfrom moving on its axis so long as the carbons remain at the requisitedistance apart.

The compound groove in the pulley P. is

constructed for the reception of two cords, the

one above the other, the narrow groove G. for the cord H. while theenlarged portion of the groove nearer the periphery of the pulley isfluted or milled at G. in the direction of the axis of the pulley forthe two fold purpose, first for receiving the cord 0. supporting theupper and lower carbon holders B and O. and secondly, in order that thegrooved bar Q. attached to the cord H. or an expanded portion of thecord such as a knot, may engage therewith.

The positive and negative wires are attached to terminals secured to thelamp frame in the ordinary manner, and in any convenient position, andwhen the full strength of the electric current is transmitted throughthe coil of the solonoid D. the plunger or core E. of the same is raisedto the full height, thereby operating the lever L. accordingly and bythe cord H. being attached to the opposite end of lever L. and afterpassing over the pulley P. in the groove G. is secured to the leverL. bywhich tension is put upon the cord II. and spring S. by the cord raisingthe last named lever. lVhen the end of lever L. is raised in the mannerdescribed, the grooved bar Q or an expanded portion of the cord H.engages with the fluted or milled portion G. of compound groove, and atthe same time moves the pulley P. some distance in the direction ofcurved arrow, thereby operating the cord 0. resting in the expandedportion of the compound groove in the same direction, th-us mo ving thecarbons B and O. apart and thereby forming the arc. The upper carbonholder B. is heavier than the bottom carbon holder O and when electriccurrent is switched off the lamp, the carbons in consequence cometogether automatically by gravity, but when the current is switched on,the carbons are separated a distance in proportion to the strength ofthe electric current or electro magnetic influence in the coil of thesolenoid, so that as the carbons B and O. are consumed, the are or spacebetween the two carbons becomes longer, therefore the resistance to theelectric current passing from one carbon to the other becomes greater,thereby reducing the strength of the current in the solenoid D. thusallowing the plunger or core E. to descend and operate the levers L andL. in a downward direction, a distance in proportion to the reducedmagnetic influence in the coil of the solenoid D. When the strength ofthe current or electro magnetic influence in the solenoid D. is reducedso as to allow the lever L. to rest upon the adjustable stop K. thetension and therefore the grip of the cord H. in the groove G. isreduced so that the positive engagement of the grooved bar Q. with theflutes at G. is withdrawn, thus liberating the pulley P. to such anextent that by the top carbon holder and carbon B. being heavier thanthe bottom carbon holder and carbon 0. they are allowed to approach eachother, and by the reduction and adjustment of the distance between thecarbons to thus maintain the arc. By the reduction in thedistancebetween the carbons in the manner described the electro magneticinfluence in the solenoid is again increased, causing the plunger orcore E. to rise and again operate the leversL and L. in the manner asbefore described such a distance that the tension of the cord H isincreased, thus gripping the pulley P and causing the grooved bar Q. orits equivalent on the cord H. to engage with the fluted or milledportion G. by which means the arc or distance between the carbons isbeing continually adjusted and a steady and regular light maintained.

What I claim is- 1. In combination, in an arc lamp, the upper and lowercarbon holders, the pulley, the suspending cord connected to the carbonholders and passing over the said pulley, the solenoid, the lever L,connected to the core thereof, and the brake band connected to the leverand embracing the pulley, substantially as described.

2. In combination, in an arc lamp, the upper and lower carbon holders,the pulley, the suspending cord connected to the carbon holders andpassing over the said pulley, the solenoid, the lever L, connected tothe core thereof, and the brake band connected to the lever andembracing the pulley, said brake band having an enlarged portion toengage the pulley, substantially as described.

3. In combination, in an arc lamp, the upper and lower carbon holders,the pulley having the deep groove G, and the outerportion G, thesuspending cord connected with the carbons and passing over the pulleyin the outer portion G thereof, the lever L, the solenoid having a coreconnected thereto and the brake band connected to the lever and passingaround the pulley in the deep groove thereof, substantially asdescribed.

4. In combination, the upper and lower carbon holders, the suspendingcord, the pulley having an outer portion G to receive the said cord andhaving a deep groove G, the lever, the solenoid having its coreconnected thereto, and the brake band connected with the lever andpassing around in the deep groove of the pulley said band having anenlarged portion thereon,substantially as described.

5. In combination, thecarbon holders, the suspending cord therefor, thepulley f or said cord, the lever L, the solenoid havingits coreconnected thereto, the lever L under spring tension and combined withthe lever L, and the brake band connected at one end with the lever L,and at the other end with the lever L, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

F. T. SCHMIDT. Witnesses:

JNo. GILL, E. G. RHODES.

